Loading-coil and case therefor.



S. B. KENT. LOADING c o|L AND CASE THEREFOR.

APPLlCATlON FILED SEPT-.12. I914.

Patented Jam. 18, 1916 Fig.

J J WJ E art s B. KENT.

LOADING COIL AND CASE THEREFOR. APPLICATION FILED SEPT. 12. 19x44 Patented Jan. 18, 1916.

2 SHEETS-SHEET 2. r/ z. v

W/fneaseS: 52%. ML

- UNITED STATES PATENT oi rion.

STANLEY B. KENT, OF NEW YORK, N. Y.,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO

WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

Specification of Letters Patent.

LOADING-COIL Aim case THEREFOR.

, Patented Jan. 18, 1916.

Application filed September 12, 1914. Serial No. 861,394.

To all 'whom it may concern: 7

Be it known that I, STANLEY B. KENT, a

' citizen of the United States, residing at New York, in the county of New York and State fof New .York, have invented certain. new

and useful Improvements in Loading-Cells and Cases Therefor, of which the following is a full,- clear, concise, and exact descrip- 7 tion.

This invention relates to air-gap loading coils, that-is to say, coils having one or more gaps in their cores, and its object is to provide a case therefor of the best shape and of minimum dimensions consistent .with the maintenance of coilefiiciency.

The invention has been applied, for ex- I ample, to a certain type of loading coil having a-toroidal .col'e formed of semi-circular sections separated by airaps. There are in such a coil two gaps at iametrically opposite points in the core. Loading coils constructed in this way have been found especially useful in conjunction with amplik thereof are subj ected, to opposin I currents; flowing in the side circuits. T is is 'because of magnetic leakage creating eddy current and hysteresis losses in the material ofthe case, thereby im airing the efliciency "of the coils. The ,di culty is especially I present in-loadingcoils of the'type herein Y consideredgha'vi i air-gaps in their cores,'

K the-..r 8$OI t atthere is a greater tendcha ge a lessen the" tendency of theleakage l nes to enter the case-. .But merely *increaslng "the g'e' .of magnetic lines in such r the air-'gapicoils' in order to size, of the casein all its dimensions does not culty as'it case, as we as making it unwieldy without re isw infa closed core coil. It-

desirable; to enlarge the inin the case.

About any magnetic source, such as an proportionately decreasing the energy loss electromagnet or a conductor carrying electric current, surfaces may be drawn wherein the magnetic force is uniform. These are usually curved surfaces, their particular configuration depending upon the characteristics of the magnetic source. If the source,

such as a loading coil, is to be inclosed with magnetic material, such as the iron loading 0011 case, and if for a given volume inclosed -'by the case the minimum loss, due to energy dissipation in the. inclosing material, is to be obtained, the contour of the inclosing material should be such that its inner surface coincides approximately with a surface of uniform magnetic force inclo sing the given volume.

. This inventionis based in part upon the foregoing principle. To express it in another way, the invention provides a casing so shaped that the magnetic leakage lines are substantially uniformly distributed over I the inner surface of the case adjacent to the coil, the shape being such that the innersurface of the case has a contour graduated as to distanee from the coil and being at a greater distanceadjacent the air-gap than elsewhere.

with the cover removed and partly in section .along the line 11 ofFig. 2; Fig. 2 is a side elevation with the casing in section along the line 2-2 of Fig. '1; and Fig. 3 is' .afragmentary view front elevation in sectionalong line 3 3 of Fig. 1. p

' Referring to the drawings, a .casing 1 =hav'in'ghthree compartments, 2, 3 and 4 is provided for two side circuit loading coils Band 6, and onephantom circuit loading coil 7 respectively. The compartments are formed of the outer walls of the casing and inner partitions 8. A single cover 9 com f letes the inclosure for all the coils, being held to the casing by bolts 10, 10. The coils shown in the drawings are of a type I having a toroidal core with two diametriafi'ord a satisfactory solutionofthe diiii-- e'atly liner-eases the cost of the cally oppositeair-gaps maintained by gapjspa'cersll and'12. Spacing'blocksof wood within their compartments. One of the blocks 13 rests in the bottom of the coil compartment. Four other blocks, 14, 15, 16 and 17, are arranged around the sides of the coil. shape that they suspend the loading coils farther away from the bottom and top walls of the compartments than from the side wall 18, 19. The distance of the coils from the walls 20 and 21 is likewise greater than the distance from the side walls 18 and 19. The greatest distance between the coil and the casing is opposite that part of the coil which includes the air-gaps, and the least is opposite that part of the coil which is farthest away from the air-gaps. After the coils have been placed in their compartments, the casing is filled with an insulating compound up to the line 23. An insulating partition plate 24: is then placed over the coils, this partition resting upon the ledge 25 of the casing. are then brought through bushings 27, piercing this plate and the appropriate connectionsmade to the outside of the casing through bushings 28. Certain of the connections between the coils are made by terminal conductors passing through bushings 30 in the inner partitions 8. The casing is finally filled up to a point 32, near the top, by another layer of insulating compound and the cover bolted in place. The case may be suspended as shown on a pole 34 by means of brackets 35 and bolts 36.

The inner surface of each compartment, it is noted, conforms generally to a flattened ellipsoid, the long aXis (A-B, Figs. 2- and 3) of which is coincident with a line extending through the centers of the two airgap spacers 11, 12. The magnetic lines which escape between adjacent poles through space external to the gaps, will spread to a small extent toward and into the case. This leakage tendency is greatest close to the gaps when the poles are strongest, but at these points the distance between These blocks are of such size and- The terminal wires 26 of the coils iaeaaia the core and case is greatest. On the other hand, at points farther away from the gaps, the tendency to leakage gradually diminishes and likewise the distance between the core and casing gradually diminishes. The mag netic leakage lines are thus spread uniformly over a wide area of the case with a consequent reduction in the s'o-called potting loss, and the case is no larger in any of its dimensions than necessary to gain the required efficiency of the loading coils within it.

What is claimed is:

1. The combination with a toroidal loading coil having a magnetic core with a nonmagnetic gap therein, of a case of magnetic material for said loading coil and conforming generally to the contour of the coil, said casing being elongated so as to be located at a greater distance from the coil adjacent the gap than elsewhere.

2. The combination with a toroidal loading coil having a core of magnetic material with a non-magnetic gap, of a casing of magnetic material for said loading coil, said casing having a contour coinciding approximately with a surface of uniform force due to magnetic leakage from the coil.

3. The combination with a toroidal loading coil having a core of magnetic material with a non-magnetic gap, of a casing of magnetic material for said loading coil, said casing having a contour graduated as to distance from the coil so that, for a given value of hysteresis and eddy current losses in the casing due to magnetic leakage lines, the volume inclosed by the casing is sub stantially a minimum.-

In witness whereof, I hereunto subscribe my name this 11th day of September, A. D. 1914.

STANLEY B. KENT.

Witnesses ALICE HAZLEY, NANCA E. TUTHILT. 

